Stock Incentive Plans - Schedule of Stock Options Valuation Assumptions Using a Black-Scholes Option Pricing Model (Details) - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility, minimum	52.80%	53.01%
Expected volatility, maximum	60.12%	59.40%
Weighted-average risk-free interest rate, minimum	2.33%	2.22%
Weighted-average risk-free interest rate, maximum	2.69%	2.31%
Underlying common stock fair value		$ 0.63
Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	5 years 8 months 12 days	6 years 3 months 18 days
Underlying common stock fair value	$ 6.63
Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	7 years 7 months 6 days	8 years 7 months 6 days
Underlying common stock fair value	$ 18.70